1. Field of the Invention
This invention relates to a bearing clamping assembly and, more particularly, to an assembly for clamping a shaft bearing race to a shaft on a gas turbine engine.
2. Description of the Prior Art
In prior art apparatus having a rotating shaft supported by a roller bearing, one of the races of the bearing is designed to rotate with the shaft by virtue of an interference fit between the shaft and the race. In the event of bearing failure, the heat generated by the failed bearing causes the race to expand, thereby allowing it to rotate relative to the shaft. Such bearing race/shaft relative rotation could lead to an actual severing of the shaft, thereby resulting in failure or malfunction of the apparatus.
The prior art addressed this potential problem by rigidly clamping the bearing race to the shaft. By way of example, in a gas turbine engine having a rotating turbine shaft supported by a roller bearing, one end of the bearing race was abutted against a shoulder on the turbine shaft. The other end of the race was engaged by a rigid cylindrical member, the other end of which abutted a shoulder on the compressor shaft. A locknut on the compressor shaft was torqued to provide a primary joint clamping load between the turbine shaft and the compressor shaft. The path of the joint clamping load through the turbine shaft, bearing race rigid cylindrical member and compressor shaft, thereby rigidly clamped the bearing race to the turbine shaft to prevent race/shaft relative rotation in the event of bearing failure.
Although the above-described configuration effectively prevented race/shaft relative rotation during periods of bearing failure, the number of contact points involved in establishing the requisite joint clamping load through the above described path made proper compressor shaft-turbine shaft alignment difficult to accomplish. The instability which resulted from the alignment difficulties resulted in engine vibration problems. The problem of effectively preventing bearing race/shaft relative rotation without significantly affecting the joint clamping load between the compressor shaft and the turbine shaft is overcome by the present invention.
It is an object of the present invention to provide a bearing clamping assembly which effectively prevents relative rotation between a turbine shaft and the race of a turbine shaft bearing without affecting the joint clamping load between the turbine shaft and the compressor shaft.
A further object of the present invention is to provide such a bearing clamping assembly which is economical to produce and which does not increase the weight or assembly time of the engine.
A further object of the present invention is to provide such a bearing clamping assembly which utilizes existing component parts.